/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#ifndef NET_INSTAWEB_REWRITER_PUBLIC_SCRIPT_TAG_SCANNER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_SCRIPT_TAG_SCANNER_H_

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/html/html_element.h"

namespace net_instaweb {
class HtmlParse;

class ScriptTagScanner {
 public:
  enum ScriptClassification { kNonScript, kUnknownScript, kJavaScript };

  // Bit flags that specify when the script is to be run
  enum ExecutionModeFlags {
    kExecuteSync = 0,
    kExecuteDefer = 1,
    kExecuteAsync = 2,
    kExecuteForEvent = 4  // IE extension. If this is set,
                          // script will not run in browsers following HTML5,
                          // and will run at hard-to-describe time in IE.
  };

  explicit ScriptTagScanner(HtmlParse* html_parse);

  // Examines an HTML element and determine if it is a script.
  // If it's not, it returns kNonScript and doesn't touch *src.
  // If it is a script, it returns whether it is JavaScript or not,
  // and sets *src to the src attribute (perhaps NULL)
  ScriptClassification ParseScriptElement(HtmlElement* element,
                                          HtmlElement::Attribute** src);

  // Returns which execution model attributes are set.
  // Keep in mind, however, that HTML5 browsers will ignore
  // kExecuteDefer and kExecuteAsync on elements without src=''
  int ExecutionMode(const HtmlElement* element) const;

 private:
  // Normalizes the input str by trimming whitespace and lowercasing.
  static GoogleString Normalized(const StringPiece& str);

  bool IsJsMime(const GoogleString& type_str);

  DISALLOW_COPY_AND_ASSIGN(ScriptTagScanner);
};

}  // namespace net_instaweb

#endif  // NET_INSTAWEB_REWRITER_PUBLIC_SCRIPT_TAG_SCANNER_H_
